1. Technical Field of the Invention
The present invention relates to a method of fastening a vehicular lighting device, comprising a lamp body and front lens, using a screw. Also, the present invention relates to a device for fastening the screw.
2. Description of the Related Art
A lighting device such as a headlamp is assembled as follows. After predetermined members such as a reflector (not shown) are housed in the lamp body 1 as shown in FIG. 11A, the seal groove 3 is filled with liquid seal material 4. Then the seal leg 6 is engaged with the seal groove 3, and the front lens 5 is coupled to the lamp body 1 by applying pressure as shown in FIG. 11B. Next, as shown in FIG. 11C, the front lens 5 and the lamp body 1, which comprise a vehicular lighting device, are inverted, and as shown in FIG. 12, the screw hole 6a is formed at a predetermined position in the seal leg 6 of the front lens 5, so that when the fastening screw 7 is screwed into the screw hole 6a with the driver 8, the screw can be fastened.
However, the aforementioned conventional screw fastening method is disadvantageous in that the vehicular lighting device comprising the front lens 5 and the lamp body 1 is coupled together by applying pressure, and the device must be inverted so that the lamp body 1 can be fastened to the front lens 5 and the screw hole 6a using fastening screw 7, which takes time and labor in the assembly of the lighting device.
Further, the following problems may be encountered. Since, during the screw fastening process, the lighting device is inverted, and the seal groove 3 is directed downward, there is a possibility that the seal material 4 may drip from the seal groove 3 in the process of fastening the screw. Therefore, it is necessary to pause the screw fastening process until the seal material 4 has solidified, causing a delay in the screw fastening process.
The present invention has been accomplished in order to solve the above problems caused in the prior art. It is an object of the present invention to provide a method and device of fastening a screw between a vehicular lighting device body and lens while keeping the sealing material from dripping.
In order to accomplish the above object, the present invention provides a method of fastening a screw between a vehicular lighting device body and lens, comprising the steps of: holding a lamp body by a body holding means so that a seal groove is directed upward; positioning a front lens using a lens holding means, so that a seal leg of the front lens is directed downward, and lowering the lens toward the lamp body; pressing the seal leg of the front lens and the seal groove of the lamp body together via seal material; positioning a fastening screw so that it is directed upward through the lamp body toward the front lens; and attaching the lamp body to the front lens by the fastening screw.
Also, the present invention provides a device for fastening a screw between a vehicular lighting device body and lens comprising: a body holding means for holding a lamp body so that a seal groove is directed upward; a lens holding means for positioning a front lens so that a seal leg is directed downward, lowering the front lens toward the lamp body held by the body holding means, and pressing the seal leg into the seal groove via a seal; and a screw fastener element for fastening a screw between the lamp body and the front lens when the fastening screw is positioned pointing upward through the lamp body toward the front lens.
According to the above structure, the lamp body and the front lens are pressed together so that the seal leg is engaged with the seal groove while the seal groove is open upward, and the screw fastened from beneath the lamp body, through the lamp body and into the front lens. Accordingly, there is no possibility that the seal material drips out from the seal groove.
Unlike the conventional attaching and screw fastening process, it is unnecessary to invert the vehicular lighting device assembly. Therefore, the process can be transferred to the screw fastening process immediately after the lamp body and front lens are assembled together.
The present invention also provides as a component of the vehicular lighting device screw fastening apparatus, the screw fastener element comprising: a screw fastener element case capable of being elevated by an elevating mechanism; a rod-shaped rotary bit extending upward and pivotally supported by the element case, having an engaging protrusion at the forward end thereof, capable of engaging with an engaging groove formed in the head of the fastening screw; and a cylindrical bit holder incorporated into the element case which is capable of moving in the vertical direction, and extending in such a manner that the cylindrical bit holder surrounds the rotary bit. The cylindrical bit holder may, for example, be within a guide path, which is aligned with a position at which the fastening screw is fastened to the lamp body held by the body holding means.
The screw fastener element (bit holder) is elevated by the elevating mechanism to a position aligned just beneath the estimated position of the lamp body, which is held by the body holding means, to which the fastening screw is to be inserted, that is, the screw fastener element is elevated by the elevating mechanism into a position just beneath the fastening screw insertion hole provided in the seal leg of the front lens. Then, the bit holder is elevated in the guide path until the forward end portion of the bit holder comes into contact with a predetermined bit holder contact portion in the guide path, or the forward end portion of the bit holder comes into contact with the lamp body exposed to the guide path, at which point the bit holder cannot be elevated any more. An engaging protrusion at the forward end of the rotary bit housed in the bit holder is engaged with an engaging groove formed in the fastening screw head, so that the rotary bit and the fastening screw integrally rotate in the circumferential direction. Therefore, when the rotary bit is elevated while it is rotating, the fastening screw engages with and pierces the lamp body (specifically, the wall on which the seal groove is formed) and is screwed into a predetermined screw insertion hole formed in the seal leg of the front lens.
The present invention also provides as a component of the vehicular lighting device screw fastening apparatus an air suction means for holding a supplied fastening screw in a vertical arrangement within the bit holder.
A downward air current created by the air suction means in the bit holder holds the fastening screw, supplied to the forward end portion of the bit holder, in a vertical arrangement, so that the engaging groove of the screw head and the engaging protrusion at the forward end of the rotary bit can be easily engaged with each other.
In the present invention, the body holding means has a lower jig for holding the lamp body so that the seal groove is directed upward and a jig support stand for holding and positioning the front lens sot that the seal leg is directed downward, and an elevating mechanism for elevating the upper jig. The present invention also includes a rodless air cylinder for elevating the screw fastener element, which is arranged in parallel with the screw fastener element at a lower position of the jig support stand. The air cylinder is supported by a horizontal oscillating mechanism so that the screw fastener element can be manipulated in the horizontal direction. The present invention further includes a screw inversion supply mechanism with a screw dropping port, fastening screw, which is supplied by a screw supply machine with the screw head directed upward, dropped and supplied to a forward end section of the bit holder of the screw fastener element. The screw inversion supply mechanism is arranged in a horizontal direction at a predetermined position separate from the lower jig of the jig support stand.
When the horizontal oscillating mechanism is driven, it is possible to smoothly move the screw fastener element in the horizontal direction between the screw dropping port location and the estimated screw fastening position.
The screw fastener element is maneuvered in the vertical direction, and requires space to operate. However, when a rodless air cylinder, in which no cylinder rod is required, is arranged in parallel with the screw fastener element, the entire height of the screw fastener element and its elevating mechanism can be reduced. Additionally, the air cylinder is provided with a holder guide for supporting the bit holder so that it can be maneuvered in the axial (vertical) direction.
The length of the bit holder is sufficiently long so that it can penetrate the body holding means in the vertical direction and reach the lamp body (seal groove). As a result, when the screw fastener element (bit holder) is elevated, the forward end portion of the bit holder tends to swing. Therefore, it is difficult to appropriately guide the forward end portion of the bit holder to the guide path. However, the holder guide provided in the rodless air cylinder suppresses the swing of the bit holder, so that the forward end portion of the bit holder can be appropriately guided to the guide path of the lower jig.
The aforementioned horizontally oscillating mechanism includes a two-axis scalar robot. The robot includes a first arm horizontally oscillating round a first vertical axis fixed to the jig support stand, and a second arm horizontally oscillating round a second vertical axis arranged at an oscillating forward end section of the first arm.
The operation of the first and the second arms are controlled by a drive control section of the two-axis scalar robot, so that the screw fastener element can be smoothly and effectively moved in the horizontal direction between the screw dropping port location and the estimated screw fastening position.